Ben Millar (22) was serving in a restaurant in Houston, Texas, when he received the very generous gratuity. His girlfriend Taryn Keith (21), who is eight months pregnant, said it "couldn't have happened to a better guy".

Waiter Ben Millar with girlfriend Taryn Keith

The Belfast man had been planning on a trip to Ireland once their son, Killian, is born and had been sharing his story with a customer who decided to help him out.

Taryn told the Irish Independent that the pair had started chatting about U2.

"The customer informed Ben that he had just been in Ireland to see the band. Ben jokingly said, 'Wow, I wish I could go back there for a weekend and visit my family', thinking nothing of it."

But when he went to collect the bill he was stunned to discover that the customer had left him a $750 (€706) tip, along with a hand-written note which read: "Hopefully, this can get you back to Ireland for the holidays".

His immediate reaction was shock, Taryn said.

The customer, whose name was Jeffrey, left so fast that Ben never got the chance to thank him. The couple hope that by sharing the story, Jeffrey will see how much his generosity meant to them.

Taryn said that the family hopes to visit Ireland after their son is born - her due date is January 20.

"I think it's a blessing and it couldn't have happened to a better guy than him. He works really hard," she said.